In this section we present the theory of the real-time vehicle tracking and accident detection system in the IOT environment.In the proposed system, vehicles are equipped with RFID tags and sensors to detect accident and pollution level. The interrogator, an antenna packed with a transceiver and decoder (The RFID reader), emits a signal activating the RFID tag so it can read the ID stored in it to be used to identify that specific vehicle. Multiple nodes are connected to the internet using Raspberry pi module. The timestamp signals are send to the cloud via this module. Now when the vehicle met with an accident the vibration sensor sense the level of the accident by the rate at which the accident occurs and the ultrasonic measures the distance using sound waves. Carbon sensors are used for the measurement of carbon dioxide gas and by this pollution level is detected. Using the timestamps generated by RFID nodes we can generate a real-time distance versus time plots of the particular vehicle. When we get the real-time distance versus time plotting we can derive many kinematics parameters from the same for Example, velocity here we are finding the velocity from the distance versus time plotting and also approximating the same using modified Euler’s algorithm to approximate the vehicles velocity in the next interrogation point, by doing this we are monitoring the movement of the vehicle in the high-speed expressway without using the high speed cameras and image processing algorithms. The entire hardware is designed around the Raspberry pi module. We use raspberry pi here as Raspberry pi is a low cost, credit-card sized computer and it is easy to use. And also the module is a wifi module. RFID readers are interfaced with GPIO pins of the Raspberry pi module. The timestamps which we receive when the car carrying the tag comes into the interrogation zone of the reader is given to the Raspberry pi module; a part of computations takes place at the cloud server as well for plotting the real-time graphs. Thus the detected signals from the RFID readers, vibration sensor, ultrasonic sensor and carbon sensor are given to the raspberry pi module. Raspberry pi module is connected to the cloud using Raspbian software and the information from the sensors is connected to cloud. From the cloud it will be sent to the mobile via way2sms if any abnormalities detected.